1. Field of the Invention
The present disclosure relates to electron beam detection.
2. Description of the Background Art
One type of electron beam apparatus is a scanning electron microscope (SEM). SEMs obtain an image of a sample by scanning a primary electron beam over the sample and detecting secondary electrons emitted from the sample. The image may be used, for example, for inspection or measurement of a micropattern in a semiconductor device, or for other purposes.
SEMs typically employ scintillator-type detectors for detecting secondary electrons emitted from the object being observed. When electrons impact material within the scintillator-type detector, the material emits light. The light is detected by a photon detector, such as a photomultiplier tube, which converts the light into an electric signal.
It is highly desirable to improve electron detectors for scanning electron microscopes and other apparatus.